Study Shows EMT Could Contribute to Harmful Gum Overgrowth
When gum tissue grows over the teeth, it’s called gingival overgrowth, and it puts people at risk for gum disease and oral infections, interferes with chewing, and is painful.
While it happens for different reasons, drug-induced gingival overgrowth is a well-known side effect of medications including the anti-seizure drug phenytoin, the immunosuppressant cyclosporin A, and calcium channel blockers (to treat high blood pressure) such as nifedipine.
In a new study, Boston University Henry M. Goldman School of Dental Medicine (GSDM) Professor of Periodontology and Oral Biology Dr. Philip Trackman and colleagues show a cellular process called epithelial to mesenchymal transition (EMT) could contribute to gingival overgrowth.
“EMT is a normal part of embryonic development, but in adults occurs only in disease, specifically cancer and fibrosis,” Dr. Trackman says. “EMT was never considered to contribute to gingival overgrowth before, although features of the histopathology were a strong clue for this biological process occurring in all forms of human gingival overgrowth.”
Dr. Trackman looked for loss of epithelial cell markers and gain of fibroblastic markers in the epithelium, and gain of markers of fibrosis in the connective tissue stroma in human tissue samples in vivo.
He also looked at the ability of TGF-β1, a factor that drives gingival overgrowth, to stimulate EMT in primary human gingival epithelial cells in vitro.
“Taken together, the data support our hypothesis that EMT contributes to the pathology of gingival overgrowth,” Dr. Trackman says.
In the future, Dr. Trackman hopes to interfere with EMT in mice to determine if overgrowth decreases.
The research was carried out by Dr. Siddika Selva Sume, a DSc candidate in Oral Biology and Dr. Alan Lee, a 2008 graduate of the MSD/CAGS program, with help from Associate Professors of Periodontology & Oral Biology Drs. Alpdogan Kantarci and Hatice Hasturk.